Effect of Zn2+ dopant on photon avalanche upconversion behavior of BiOCl:Er3+ crystals

Effect of divalent dopants, Zn2+ ion, on the high-order photon avalanche (PA) upconversion (UC) emission of Er3+ doped BiOCl microcrystals was investigated. XRD results indicated that Zn2+ ion dopants would mostly enter into the lattice space at low and moderate doping concentration, and began to substitute Bi3+ ion gradually at heavily doping level. Under exaction at 980 nm, the PA UC of violet, green and red emission of Er3+ ions could be observed, and the UC emission intensity increased with increasing the Zn2+ addition below 8 mol.%, then decreased with further addition. Power dependence study showed that the dopant concentration of Zn2+ had no obviously negative effect on the occurrence of PA emission. On the bases of results investigated herein, we considered that the lattice distortion by Zn2+ doping could not directly change the special PA emission of BiOCl:Er3+, but would improve the emission intensity when used as lattice modifier.